engleski

Experimental and Analytical Results of the Solar-assisted Heat Pump Performance

The paper presents an analysis of a heat pump of a type which is neither fully investigated nor widely applied. A solar-assisted heat pump with direct evaporation of the refrigerant in a solar collector uses solar energy and the ambient air as a heat source on the evaporator. Due to the high collector efficiency in the performance of solar-assisted pumps (eta_coll = 0.6 - 0.9) compared with the collector efficiency of conventional solar systems (eta_coll = 0.4 - 0.6), and due to the fact that they can operate even in cloudy weather conditions, solar-assisted heat pumps attract growing attention on the part of researchers and users. Analytical and experimental studies were carried out on a solar assisted heat pump consisting of two flat-plate solar collectors acting as an evaporator for the refrigerant R-134a, a variable-frequency reciprocating type compressor, a compact plate heat exchanger (condenser) and an electronic expansion valve. The obtained results show a great impact of solar irradiation, ambient temperature and compressor speed on the properties of the system. The COP of the heat pump is in the range from 4 to 7, depending on the system parameters settings.

solar-assisted heat pump; collector efficiency; COP

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